Investigation On Surface Nanocrystallization And Ion Implantation Of Q235 Low Carbon Steel

Most failures of materials occur on surface, including fatigue fracture, corrosion and wear etc., which are very sensitive to microstructure and properties of the surface. As a result, the surface modification of engineering materials is found to process more and more industrial applications. Nanocrystalline materials have attracted considerable interest because of their novel mechanical, physical and chemical properties originating from a large volume fraction of grain boundaries or interfaces with respect to the conventional coarse-grained polycrystalline materials. It is expected to achieve surface modification by the generation of a nanostructured surface layer, referring as surface nanocrystallization(SNC), so that the properties and behavior of materials are significantly improved. With the increasing development of surface engineering and nanotechnology, more and more researches focus on the combination of surface modification and nanotechnology.A porosity-free and contamination-free nanostructured surface layer with thickness about 25μm was fabricated on a Q235 low carbon steel plate by using surface mechanical attrition treatment (SMAT). Microstructural characterization of the nanostructured surface layer was investigated by means of X-ray diffraction (XRD), transmission electron microscopy (TEM) and optical microscopy. Then Ti ion was implanted into the SMA treated...